/*fahrcels.c (several versions) - use a conditional statement to select one of
  two calculations.  Copyright (c) 1998 Matthew Belmonte.*/
#include <stdio.h>
int main()
  {
  double fahr, cels;
  int scale;			/*'C' for Celsius input, 'F' for Fahrenheit*/
/*get input type*/
  printf("Type C to convert Celsius to Fahrenheit, or F to go the other way: ");
  scale = getchar();
/*get input, and do the appropriate calculation*/
  printf("degrees? ");
  if(scale == 'C')
    {
    scanf("%lf", &cels);
    fahr = 9.0*cels/5.0+32.0;
    }
  else
    {
    scanf("%lf", &fahr);
    cels = 5.0*(fahr-32.0)/9.0;
    }
  printf("%.3f degrees Fahrenheit is %.3f degrees Celsius\n", fahr, cels);
  return 0;
  }

/*uses logical OR to handle lowercase*/
#include <stdio.h>
int main()
  {
  double fahr, cels;
  int scale;			/*'C' for Celsius input, 'F' for Fahrenheit*/
/*get input type*/
  printf("Type C to convert Celsius to Fahrenheit, or F to go the other way: ");
  scale = getchar();
/*get input, and do the appropriate calculation*/
  printf("degrees? ");
  if((scale == 'C') || (scale == 'c'))
    {
    scanf("%lf", &cels);
    fahr = 9.0*cels/5.0+32.0;
    }
  else
    {
    scanf("%lf", &fahr);
    cels = 5.0*(fahr-32.0)/9.0;
    }
  printf("%.3f degrees Fahrenheit is %.3f degrees Celsius\n", fahr, cels);
  return 0;
  }

/*uses bitwise AND to convert case*/
#include <stdio.h>
int main()
  {
  double fahr, cels;
  int scale;			/*'C' for Celsius input, 'F' for Fahrenheit*/
/*get input type*/
  printf("Type C to convert Celsius to Fahrenheit, or F to go the other way: ");
  scale = getchar()&0x5f;
/*get input, and do the appropriate calculation*/
  printf("degrees? ");
  if(scale == 'C')
    {
    scanf("%lf", &cels);
    fahr = 9.0*cels/5.0+32.0;
    }
  else
    {
    scanf("%lf", &fahr);
    cels = 5.0*(fahr-32.0)/9.0;
    }
  printf("%.3f degrees Fahrenheit is %.3f degrees Celsius\n", fahr, cels);
  return 0;
  }

/*uses toupper() to convert case*/
#include <stdio.h>
#include <ctype.h>
int main()
  {
  double fahr, cels;
  int scale;			/*'C' for Celsius input, 'F' for Fahrenheit*/
/*get input type*/
  printf("Type C to convert Celsius to Fahrenheit, or F to go the other way: ");
  scale = toupper(getchar());
/*get input, and do the appropriate calculation*/
  printf("degrees? ");
  if(scale == 'C')
    {
    scanf("%lf", &cels);
    fahr = 9.0*cels/5.0+32.0;
    }
  else
    {
    scanf("%lf", &fahr);
    cels = 5.0*(fahr-32.0)/9.0;
    }
  printf("%.3f degrees Fahrenheit is %.3f degrees Celsius\n", fahr, cels);
  return 0;
  }

/*uses a conditional expression as well as a conditional statement*/
#include <stdio.h>
#include <ctype.h>
int main()
  {
  double fahr, cels;
  int scale;			/*'C' for Celsius input, 'F' for Fahrenheit*/
/*get input type*/
  printf("Type C to convert Celsius to Fahrenheit, or F to go the other way: ");
  scale = toupper(getchar());
/*get input, and do the appropriate calculation*/
  printf("degrees? ");
  scanf("%lf", (scale=='C')? &cels: &fahr);
  if(scale == 'C')
    fahr = 9.0*cels/5.0+32.0;
  else
    cels = 5.0*(fahr-32.0)/9.0;
  printf("%.3f degrees Fahrenheit is %.3f degrees Celsius\n", fahr, cels);
  return 0;
  }

/*uses shorthand operators*/
#include <stdio.h>
#include <ctype.h>
int main()
  {
  double fahr, cels;
  int scale;			/*'C' for Celsius input, 'F' for Fahrenheit*/
/*get input type*/
  printf("Type C to convert Celsius to Fahrenheit, or F to go the other way: ");
  scale = getchar();
  scale &= 0x5f;
/*get input, and do the appropriate calculation*/
  printf("degrees? ");
  scanf("%lf", (scale=='C')? &cels: &fahr);
  if(scale == 'C')
    {
    fahr = cels;
    fahr *= 9.0/5.0;
    fahr += 32.0;
    }
  else
    {
    cels = fahr;
    cels -= 32.0;
    cels *= 5.0/9.0;
    }
  printf("%.3f degrees Fahrenheit is %.3f degrees Celsius\n", fahr, cels);
  return 0;
  }

/*THIS ONE IS FULL OF BUGS: FIND ALL OF THEM, WITHOUT LOOKING BACK!*/
#include <stdio.h>
int main();
  {
  double fahr, cels;
  char scale;
  printf("Type C to convert Celsius to Fahrenheit, or F to go the other way: ");
  scale = toupper(getchar());
  printf("degrees? ");
  scanf("%f", &((scale='C')? cels: fahr));
  if(scale = 'C')
    fahr = 9.0*cels/5.0+32.0;
  else
    cels = 5.0 * fahr-32.0 / 9.0;
  printf("%d degrees Fahrenheit is %d degrees Celsius", fahr, cels);
  return 0;
  }
/*******
ANSWERS:
0. ctype.h not included, so no prototype for toupper()
1. semicolon after function definition
2. getchar() squeezed into a char, instead of an int
3. scanning into a double with a float specifier
4. operand of reference is not an lvalue
5. assignment operator used instead of equality
6. order of operations
7. doubles as arguments for %d conversion
8. no newline
9. no comments
*******/